Amazon Rainforest

The Amazon rainforest is the world’s largest tropical rainforest, spreading across 2.3 million square miles in parts of nine South American countries, a region also known as Amazonia. It is located inside the Amazon basin, the drainage area of the Amazon River and its tributaries. The Amazon rainforest is one of the world’s most iconic habitats, home to millions of species of animals, plants, fungi, and microbes. The Amazon is a vital ecosystem not only because of its immense biodiversity, but also because its trees help produce oxygen and absorb carbon from the air, helping to regulate climate at the global scale. The area is also home to numerous groups of Indigenous people in Brazil, Peru, and other countries.

Despite the Amazon’s importance to the planet, it is being deforested and destroyed at a rate that alarms many scientists. As more of the Amazon is destroyed, an increasing number of endemic species are threatened with extinction. It is believed that as many as half the species in the rainforest have yet to be identified by scientists, meaning numerous species are likely dying off without ever being recorded. The loss of Amazon rainforest habitat is also linked to climate change, both exacerbating and being exacerbated by global warming. Many groups and governments are working to try to end human-caused deforestation and fight wildfires that also contribute to the Amazon’s destruction.

Background

Rainforests are found in many different parts of the world. In fact, rainforests are located on every continent, except Antarctica. Although most people associate rainforests with warm, tropical climates, they exist in temperate climates as well. Temperate rainforests receive heavy rainfall and can be made up of coniferous or broad-leaf trees. They exist in regions both north and south of the equator.

Tropical rainforests, like the Amazon, are located closer to the equator, where the climate remains warm and humid all year long. To be classified as a tropical rainforest, a region must include four main parts: a forest floor, an understory, an upper canopy, and an emergent layer. The forest floor is dark and heavily shaded from the tree canopy above. Very little light reaches this part of the forest, allowing dead plant and animal materials to decay quickly. The understory is also dim, but it does receive some sunlight. Plants growing at this level often have large leaves to help them catch and absorb more light. The upper canopy is the main layer of plant life made up of the tops of trees. These trees prevent much of the light from reaching the bottom two layers of the rainforest. The Amazon rainforest canopy is so thick that it can take up to ten minutes for rain to reach the forest floor after it starts falling. Many animals, such as frogs and birds, live in the canopy layer because food is plentiful there. The emergent layer includes the tallest trees, some of which can grow to be 200 feet (61 meters) tall.

Rainforest habitats cover only about 6 percent of the planet’s surface, but they contain about half the world’s known plant and animal species. Many of the plants and animals in these habitats cannot survive in other places. For example, the Brazil nut tree grows only in the Amazon rainforest. For this reason, rainforest habitats are vital to the health of Earth’s biodiversity.

Another reason that rainforests are important is that they absorb carbon dioxide and produce huge amounts of oxygen. The large number of trees and other plants in a rainforest help filter contaminants from the air, and their root systems help to stop erosion and filter groundwater. These features have both local and global environmental impact.

Overview

The Amazon rainforest is roughly 2.3 million square miles (6 million square kilometers) in size. That means that the Amazon rainforest is close in size to the lower forty-eight states of the United States. Most of the Amazon rainforest is located in Brazil, South America’s largest country, but it also covers parts of Peru, Ecuador, Columbia, Venezuela, Bolivia, Guyana, Suriname, and French Guiana. The rainforest covers about 40 percent of Brazil’s land area. The Atlantic Ocean borders the rainforest on its eastern side and the Guiana Highlands border it to the north. The Andes Mountains lie to the west and the Brazilian central plateau lies to its south. The Amazon River, which is the second-largest river in the world, flows through the center of the rainforest and its many tributaries stretch throughout the region.

The Amazon rainforest is famous for its biodiversity. Common trees in the rainforest include rosewood, Brazil nut, palm, Amazon cedar, and rubber trees. Some other notable plants that grow in the Amazon include the cacao tree, the lobster claw flower (or Heliconia flower), the coffee plant, and numerous species of orchids.

The rainforest also sustains many animal species. It is home to more than 400 known types of mammals, with some of the most notable including jaguars, giant anteaters, and various species of monkeys, sloths, and capybaras (large rodents). Snakes, frogs, and lizards—including iconic species such as the anaconda and the poison dart frog—live throughout the Amazon. Birds are some of the most common animals in the Amazon rainforest, with about 1,300 known species calling it home. These include macaws and other colorful parrots, which have historically been popular as pets. Even more diverse are the region's insects, with some scientists estimating that the rainforest could be home to about 2.5 million or more unique insect species. The rainforest biome is also home to aquatic species such as the black caiman, various fish species, and the endangered Amazon river dolphin.

Many Amazon rainforest species are of economic importance for humans. People harvest cacao beans to make chocolate and the beans of the coffee plant to make coffee. The sap of the rubber tree is harvested to create natural rubber. Many other tree species have been valued for their timber. Furthermore, scientists have used chemical compounds identified in various plants from the region to create everything from life-saving medications to beauty products.

Human Impact

Indigenous peoples have lived in the Amazon rainforest for thousands of years. It was long thought that the groups living there before the arrival of Europeans were mostly small in numbers and subsisted as hunter-gatherers, with little large-scale impact on the natural environment. However, later research has suggested that there was in fact a considerable human population in the region and that in some places they significantly impacted the ecology of the forest, including through intentional burning to clear land for agriculture.

As Europeans began exploring and colonizing South America from the 1490s on, Indigenous populations were decimated by disease and any large, centralized societies collapsed. Nevertheless, hundreds of Indigenous groups, including the Yanomami, Munduruku, and the Uru Eu Wau Wau, continued to live in the Amazon rainforest over the following centuries. These peoples tended to maintain semi-nomadic lifestyles with a relatively low environmental footprint. Some had little to no contact with global society, as the massive Amazon River basin area remained relatively undeveloped well into the twentieth century.

Settlement in and around the Amazon rainforest began to increase in the late 1800s and early 1900s, driven by rising demand for the rainforest's natural resources as well as growth in South America's overall population. Brazil, as the country controlling the majority of the Amazon, played a key role in this development. By the 1960s, overpopulation in southern Brazil led to various policies encouraging small-scale farming and cattle ranching in the rainforest. In 1970, the Brazilian government began a major road construction project that included the Trans-Amazon highway, further opening the rainforest to industry, commerce, agriculture, and resettlement initiatives. In 1978, eight countries signed the Amazonian Cooperation Treaty to promote economic development in the rainforest.

These projects did lead to strong economic growth in the region. However, they also displaced Indigenous populations and often polluted the environment. Accelerating deforestation began to draw concern from environmentalists. By the 1980s, scientists with Brazil’s Instituto Nacional de Pesquisas da Amazônia (National Institute of Amazonian Research, or INPA) and other organizations provided evidence that rapidly accelerating deforestation was destroying crucial plant and animal habitats. Social activists such as Chico Mendes also brought global attention to the cause of preserving the Amazon rainforest. In response, the Brazilian government took some steps toward promoting sustainable land use, including the National Plan of Agrarian Reform in 1985, which set aside forest reserves for activities such as collecting rubber and Brazil nuts. However, the murder of Mendes in 1988 indicated the great tensions between those seeking to protect the forest and ranchers and other business interests promoting land clearing.

By the turn of the twenty-first century, the movement to "save the rainforest" was a well-known cause worldwide. Along with INPA, international environmental organizations such as the World Wildlife Fund, the Rainforest Action Network, and the Nature Conservancy, worked to draw international attention to the Amazon. While the initial focus was largely on preserving biodiversity and protecting endangered species, increasing recognition of the threats posed by climate change brought heightened attention to the Amazon rainforest's importance to global climate as well. Brazil and other countries in the area often officially recognized the benefits of preserving the forest, yet still struggled to reconcile conservation goals with immediate economic and political pressures. Even in parts of the rainforest that were formally protected, illegal activities continued to accelerate deforestation and pollution. In the early twenty-first century, clearing of land for cattle ranching was considered the major driver of Amazon deforestation. Logging for timber, crop growing, mining, and oil exploration were other damaging industries.

By the early 2010s, scientists increasingly warned of a catastrophic scenario if the destruction of the Amazon continued unabated. Some studies suggested that the rainforest was approaching the tipping point of dieback, or the state in which a forest is so weakened that it naturally declines and gives way to other ecosystems. In such a scenario, the Amazon rainforest would lose its resilience to drought, leading to increasing wildfires that would in turn further accelerate deforestation, creating a feedback loop that could ultimately result in the region's transformation into a savannah-like environment. Scientists also noted that the loss of the Amazon would also cause billions of tons of carbon stored in the rainforest's plant matter to be released into Earth’s atmosphere, exacerbating global warming. In 2023, a study published in the journal Science found that up to 38 percent of the Amazon had been damaged by factors such as human activity, fire, and drought.

Numerous organizations continue to work toward protecting the Amazon rainforest. Indigenous activists have been at the forefront of many campaigns, although they have often faced violence for their attempts to stop illegal activities in the region. Nonprofit groups such as the Forest Stewardship Council, the World Wildlife Fund, and the Rainforest Alliance also continue to help to raise awareness about the threats to the rainforest and lobby governments to protect the area. Other groups have focused on developing sustainable economic opportunities for people living in and around the Amazon, and thereby decreasing demand for illegal logging and ranching.

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